Zika Virus

Zika Virus

What is Zika?

Zika is a virus that is spread to people primarily through the bite of an infected Aedes species mosquito. It is a mosquito-transmitted infection related to dengue, yellow fever, chikungunya and West Nile virus that was first discovered in Uganda in 1947 and is common in Africa and Asia. It did not begin spreading widely in the Western Hemisphere until last May, when an outbreak occurred in Brazil.

What are the symptoms of Zika?

Infection with the Zika virus may cause a viral illness with the most common symptoms of fever, rash, joint pain, or conjunctivitis (red eyes). Symptoms typically begin 2 to 7 days after being bitten by an infected mosquito. Only about 1 in 5 people infected with Zika will get sick and for people who get sick, the illness is usually mild. For this reason, many people might not realize they have been infected.

How is Zika transmitted?

Zika is primarily transmitted through the bite of infected Aedes mosquitoes, the same mosquitoes that spread Chikungunya and dengue. These mosquitoes live in urban areas, are aggressive daytime biters and they can also bite at night. Mosquitoes become infected when they bite a person already infected with the virus. Infected mosquitoes can then spread the virus to other people through bites. It can also be transmitted from a pregnant mother to her baby during pregnancy or around the time of birth, but this is rare. Federal health officials are studying how some mothers can pass the virus to their babies.

Can the Zika virus be sexually transmitted?

Yes, but experts suspect it is rare. Experts believe that the vast majority of all Zika infections are transmitted by mosquitoes, not sex. In early February, health officials in Texas announced that a traveler who had returned to Dallas from Venezuela apparently had infected a sexual partner.
The CDC issued tentative new guidelines suggesting that pregnant women avoid contact with semen from men who have recently returned from areas with Zika transmission. According to the CDC men returning from these regions should consider using condoms during sexual activity.

Who is at risk of being infected?

Anyone who lives in or travels to an area where Zika virus is found and has not already been infected with Zika virus can be infected.

What countries have Zika?

Specific areas where Zika virus transmission is occurring are often difficult to determine and are likely to change over time. If traveling, please visit the CDC Travelers’ Health site for the most updated travel information.

Is there a vaccine for Zika?

There is no vaccine to prevent infection from Zika.
Infectious disease researchers with the University of Miami Miller School of Medicine are actively pursuing a vaccine. Read more here.

What can people do to prevent becoming infected with Zika?

The best way to prevent diseases spread by mosquitoes is to protect yourself and your family from mosquito bites. Here’s how:

  • Wear long-sleeved shirts and long pants.
  • Stay in places with air conditioning or that use window and door screens to keep mosquitoes outside.
  • Use Environmental Protection Agency (EPA)-registered insect repellents. All EPA-registered insect repellents are evaluated for safety and effectiveness.
    • Always follow the product label instructions.
    • Reapply insect repellent as directed.
    • Do not spray repellent on the skin under clothing.
    • If you are also using sunscreen, apply sunscreen before applying insect repellent.
  • If you have a baby or child:
    • Do not use insect repellent on babies younger than 2 months of age.
    • Dress your child in clothing that covers arms and legs, or
    • Cover crib, stroller, and baby carrier with mosquito netting.
    • Do not apply insect repellent onto a child’s hands, eyes, mouth, and cut or irritated skin.
    • Adults: Spray insect repellent onto your hands and then apply to a child’s face, or use bar or roll-on repellent.
  • Treat clothing and gear with permethrin or buy permethrin-treated items.
    • Treated clothing remains protective after multiple washings. See product information to learn how long the protection will last.
    • If treating items yourself, follow the product instructions carefully.
    • Do NOT use permethrin products directly on skin. They are intended to treat clothing.
  • Sleep under a mosquito bed net if you are overseas or outside and are not able to protect yourself from mosquito bites.

What is the treatment for Zika?

  • There is no specific medicine to treat Zika virus infections. Instead, physicians recommend the following to treat the symptoms:
  • Get plenty of rest.
  • Drink fluids to prevent dehydration.
  • Take medicine such as acetaminophen to reduce fever and pain.
  • Do not take aspirin or other non-steroidal anti-inflammatory drugs.
  • If you are taking medicine for another medical condition, talk to your health care provider before taking additional medication.

How is Zika diagnosed?

  • Your health care provider may order blood tests to look for Zika or other similar viral diseases like dengue or chikungunya.
  • Those tests are sent to the Department of Health for processing.

Are you immune for life once infected?

Once a person has been infected, he or she is likely to be protected from future infections.

If a pregnant woman becomes infected with the Zika virus, will it cause birth defects?

There have been reports of a serious birth defect of the brain called microcephaly (a condition in which a baby’s head is smaller than expected when compared to babies of the same sex and age) and other poor pregnancy outcomes in babies of mothers who were infected with Zika virus while pregnant. Knowledge of the link between Zika and these outcomes is evolving, but until more is known, CDC recommends special precautions for the following groups:

  • Women who are pregnant (in any trimester):
    • Consider postponing travel to any area where Zika virus transmission is ongoing.
    • If you must travel to one of these areas, talk to your doctor first and strictly follow steps to prevent mosquito bites during your trip.
    • Inform your OB/GYN physician if you believe you might have been infected.
  • Women who are trying to become pregnant:
    • Before you travel, talk to your doctor about your plans to become pregnant and the risk of Zika virus infection.
    • Strictly follow steps to prevent mosquito bites during your trip.

For more questions and answers on Zika and pregnancy, click here.

Does Zika virus infection cause Guillain-Barré syndrome (GBS)?

Guillain-Barré syndrome (GBS) is a rare disorder where a person’s own immune system damages the nerve cells, causing muscle weakness and sometimes, paralysis. These symptoms can last a few weeks or several months. While most people fully recover from GBS, some people have permanent damage and in rare cases, people have died.

We do not know if Zika virus infection causes GBS. It is difficult to determine if any particular germ “causes” GBS. The Brazil Ministry of Health (MOH) is reporting an increased number of people affected with GBS. The CDC is collaborating with the Brazil MOH to determine if having Zika makes it more likely you will get GBS.